Exploratory analysis of predictors of patient adherence to subcutaneous interferon beta-1a in multiple sclerosis: TRACER study

ABSTRACT

Objective: The TRACER multicenter retrospective study aimed to collect data on treatment adherence in a real-life setting, in order to identify predictors of adherence at baseline.

Methods: We recruited 384 relapsing-remitting (RR) multiple sclerosis patients with at least 12 months of use of RebiSmart®. This electronic device records the performed injections and assesses adherence as the percentage of ‘not missing doses’, through the connection to the iMed database. Subjects with at least 80% of completed doses at the 12 month of therapy were defined ‘treatment adherents’.

Results: After 12 months, 89.3% of patients were adherent; 93.2% of patients aged 26–40 years at baseline were adherent (vs 79% of the ≤25 and 87.5% of the ≥41 year olds; p = 0.006). Furthermore, 90.5% of patients with a baseline Expanded Disability Status Scale (EDSS) score <4 showed ≥80% adherence (vs 71.4% in those with EDSS score ≥4; p = 0.016). Fifty-four percent of the patients who were not adherent after 3 months were also not adherent after 12 months (OR 16.8; CI 95%:7.1–39.8).

Conclusions: Patients aged 26–40 years and with an EDSS score <4 at baseline were the most adherent. The status of ‘treatment adherent’ in the first 3 months was predictive of higher adherence in the long term.

KEYWORDS:

• Disease-modifying drugs
• interferon beta
• patient adherence
• real-life setting
• rebismart® injection device
• relapsing-remitting multiple sclerosis

Declaration of interest

E Cocco has received honoraria from Bayer, Biogen, Genzyme, Merck, Novartis and Teva, for consulting services, speaking and travel support. She has received research grant support from the Italian MS Foundation. V Direnzo has received honoraria from TEVA. L Moiola has received honoraria for speaking from Sanofi Aventis, Biogen Idec and Merck. R Lanzillo has received honoraria from Bayer Shering, Biogen, Merck-Serono, TEVA, Genzyme, Almirall and Novartis for lectures or scientific boards. P Perini has received speaking honoraria and/or consultant fees from Teva, Biogen, Novartis, Serono, Genzyme. S Malucchi has received honoraria from Biogen, Merck-Serono, TEVA, Genzyme. G Borriello has received research grants from Almirall and Merck-Serono. E Portaccio serves on a scientific advisory board for Biogen, Merck Serono and Genzyme, has received honoraria for speaking from Biogen, Novartis and Genzyme, and receives research support from Merck Serono. G Fenu has received honoraria for consultancy from Novartis, for speaking from Merck Serono and Teva and travel support from Bayer, Biogen, Genzyme, Merck, Novartis and Teva. M Trojano has received honoraria for consultancy or speaking from Biogen, SanofiAventis, Merck Serono, Novartis, Genzyme, TEVA, and Bayer-Schering and research grants from Merck Serono, Biogen, and Novartis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.